Optimizing frequency of CD4 assays in the era of highly active antiretroviral therapy

Current HIV guidelines recommend monitoring CD4 counts every 3-4 months. In the era of highly active antiretroviral therapy (HAART) and HIV PCR, this retrospective study reexamines the required frequency of the CD4 assay. Predictor variables, including age, previous CD4 count, HIV viral load (VL), time interval since last VL and CD4 count (TINT), and antiretroviral history, were abstracted. A recursive partitioning-based regression tree analysis was used to determine if the absolute current CD4 count was above or below the age appropriate Pneumocystis jiroveci pneumonia (PCP) prophylaxis cutoff. We analyzed concurrently obtained VLs and CD4 count including 601 results from 43 HIV-infected children aged 1-